B.N.
H.,
The best I can recall when my 20 month old was doing that, it was around that age. If she is doing it at home, might I suggest instead of time out... which you said the school is doing, she is not going to understand that, instead check to see if she has teeth coming in and if so, let the daycare know, and provide them with the teething medicine, also tylenol for infants for the pain. I would buy two bottles, and empty one into the other than measure out just enough for the hours she is there, and tell them to not throw away the bottle, but give it back to you for the next time. That way you will not worry about them overdoseing your child. ;-)
If she is doing it for other reasons, such as to just bite, maybe ask them to stick a cold ice cube to her mouth, and tell her no biteing, that is a no no, but they need to be on her level, knealing down for her to understand what she did wrong, and it needs to happen as soon as she bites someone. Then ask her to hug whoever she bit and try to work with her on saying "I'm sorry" and then congratulate her for responding with a hug and you tell her "that is a sweet girl", in a soft spoken voice. You may want to practice with her at home if she acts out, so she will catch on to what happens for punishment and for being a sweet girl. Mine did this at home with biteing older kids and myself, and this did work on her, she caught on quickly and quit biteing after two days. H. that helps.